Swelling affects quads strength up to 4 years post knee injury/surgery – what can you about it?

After knee injury, surgery and pathology, it’s common both as a patient and a clinician to see marked weakness of the quadriceps muscles at the front of the thigh, even following extended periods of rehabilitation. This is partly due to muscle wasting in some cases, but is also partly due to a phenomenon known as athrogenic muscle inhibition (AMI). AMI occurs in all cases of knee injury, regardless of the pathology. Why is important to minimize this? Because without good quadriceps strength and control, there is a decrease in lower leg control during walking and running, and an impairment in the normal stability and control of the knee during everyday activities and of course during recreational and sporting activities.

AMI seems to be worse immediately after knee injury or surgery, but it can actually persist for month, and sometime even years. What is even more interesting, is that studies have found that following knee injury or surgery, this inhibition of the quadriceps muscles occurs in the non-injured leg as well! Compared to the injured leg, there isn’t the same degree of muscle loss, but it does take just as long (sometime up to 4 years) to recede. What this means clinically, is that both patients and clinicians have to be careful when comparing strength in an injured to an un-injured leg, as both are likely to be impaired.

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For a long time, it was thought that AMI was caused by pain and inflammation. It was a bit of a mystery why the quads weakness persisted long after the knee was back to feeling comfortable after an injury. It is now known that the presence of swelling in the knee, in the absence of pain and inflammation, can also cause AMI. In fact, the link between knee pain and quadriceps AMI hasn’t been clearly shown in studies. From clinical studies, it has however been found that just 10ml of fluid is enough to cause the AMI to be present. This is a very small amount indeed, and would probably not be able to be detected clinically. So we know, therefore, that the presence of knee swelling, even small amounts, can have a powerful effect on quadriceps weakness and inhibition after knee injury/surgery.

So the next important question is: what can we do therefore to minimize AMI? Again from clinical studies, it has been found that local anaesthetic or aspiration of fluid from the knee can help, but unfortunately these interventions don’t always work, nor are they practical from an everyday patient point-of-view. A really interesting piece of research has been carried out however by David Rice and colleagues at the Auckland University of Technology here in New Zealand. They found that using ice on the knee (they used bags of partially crushed ice wrapped around the knee for 20 minutes temporarily reduced the severity of AMI, thereby giving a ‘window of opportunity’ to work on strengthening. This is likely to lead to more effective and quicker strengthening of the main things to remember?

   Keep the swelling down in your knee as much as possible by following the well known principles of Rest, Ice, Compression and Elevation (RICE)

   Ice the knee for 20 mins (make sure it’s the knee you are icing, not the quads muscle itself) and then do your quadriceps strengthening exercises immediately following this

   Also work on knee stability and proprioception exercises (ask your physio about these), as they can also minimize AMI)

   In cases of severe persistent swelling, knee aspiration or anaesthetic may be required to further minimize AMI.

As always, consult your Physio or health professional for appropriate advice and exercises first. 

 References:

Rice, D., McNair, P.J., Dalbeth, N. (2008) Effects of cryotherapy on arthrogenic muscle inhibition using an experimental model of knee swelling. Arthritis Care & Research, 61 (1), 78-83.

Rice, D., Mcnair, P.J. (2010). Quadriceps arthrogenic muscle inhibition: neural mechanisms and treatment perspectives. Seminars in Arhritis and Rheumatism. 40 (3), 250-266.

Rice, D. (2008) Cryotherapy reduces arthrogenic muscle inhibition following experimental knee joint infusion. Clinical Neurophysiology, 119, 90.

22 Responses to Swelling affects quads strength up to 4 years post knee injury/surgery – what can you about it?

  1. Emiljano says:

    I tried returning to american football after 8.5 months post op but my patella was giving me pain so I had to stop. It is now 16 months post op and I had a good run of pretty much pain free practices and now it’s returning and it looks like this may be the reason why because my quad especially the medial side is weaker and noticeable from the other leg. Thanks I will follow these tips and see how it goes if you have any others I would love to hear them.

  2. Andy Schmidt says:

    I guess in your rehab time you have doing a lot of quads-specific strengthening? because of the deficits relating to swelling and pain, it really is a case of often being 2 steps forward, one step back when trying to get the return of quads strength. Ideally, you should get to about 10% of the good side. Remember too that the bulk and tone may not be there, but as long as the functional strength is, then that is ok. Good luck and keep working on it, you will get there!

  3. Anibal Pflieger says:

    Many types of minor knee pain respond well to self-care measures. Physical therapy and knee braces also can help relieve knee pain. In some cases, however, your knee may require surgical repair.”“*

  4. neha says:

    i had a knee injury where fluid had accumulated around my knee. Fluid was aspirated and my leg was immobilized for a week.My quadriceps had weakened and my doctor suggestsd physiotherapy. two years later i developed chondromalacia and doctor suggested physiotherapy. my symptoms of pain and weakness reduce while during physiotherapy(which i did for 3 months as suggested by my doctor)but when i stop my exercises my symptoms come back within a month or so. This has happened twice. i feel i like my muscles are never going to get back their strength. please help.

    • Andy Schmidt says:

      Are you able to elaborate any more on what the initial injury was at all? And I guess my other question would be, is there any reason why you stop doing the exercises?
      Kind regards
      Andy

  5. WM says:

    I am a 62 year old retired firefighter with a 12 year old injury of a ruptured lower quadricep together with a small defect in the articular cartilage on the medial side. I declined surgery at the time and had my leg in a plaster cast for 6 weeks with the plaster removed I had a course of 2 local anaesthetic injections over 2 weeks followed by an aspiration of 6mls of serous fluid from the knee joint. A further 6 months of VMO rehabilitation to strengthen the knee completed the treatment. Unfortunately, the injury ended my firefighting career prematurely.

    Even know, I cannot kneel on the floor, or jog for more than 10 minutes without feeling discomfort /pain in the knee and still have tightness around the knee joint. On some occasions i still get Swelling around the knee and still have some wasting muscle in the lower quadricep.

    Do you think that my age ( 50) when the injury occurred was a contributory factor to this lack of recovery.

    Sent from my iPad, Be Happy.

    • Andy Schmidt says:

      In short..age was probably a factor, mainly because we know that unfortunately the tissues don’t heal as well as we age. Also swelling tends to be harder to get rid of, and strength harder to return too. The lack of ability to kneel and tightness around the knee joint is likely to be partly a result of deep scar tissue from the quads repairing. The intermittent knee swelling is more likely to be a result of the articular cartilage defect I suspect.
      Sorry to hear it ended your career prematurely. I guess the best I can say here is continue to make knee maintenance strengthening, balance and general core stability work an ongoing part of your exercise routine. And try and embrace other forms of cardio that don’t impact the knee as much as running does. Best of luck and hope that helps.
      Andy

  6. Abraham says:

    I had a MPFL reconstruction a year ago, following the surgery i started physical therapy for about four months and then started working out at the gym lifting weights. So far i haven’t recovered my quad strenght completely, after a year i feel kind of stuck i guess it’s due to AMI keeping me from getting stronger quad.
    I’m still doing exercises everyday and some jogging on weekends but frustrated because i’m stuck at 3/5 of quad strenght.
    I’d like to know if this is normal, will i eventually get fully recovered in the long run or this is a point of no return. what should i do?

    Sorry about my english.

    Thanks in advance.
    Regards.

    • Andy Schmidt says:

      How often are you doing your quads exercises – and have you had a physiotherapsit check them regularly to double check that you are isolating your quadriceps? normally after 1 year you would expect about 80-90% of your quads strength to have returned, if you have been really diligent with the rehab…let me know. thanks, Andy

    • Andy Schmidt says:

      You will get there. Keep at it and keep the chin up!

  7. LIz says:

    I had lateral release Sep 30, 2014.. After my first follow up visit of 10 days. Doc sends me to PT by then my Quad muscle had waisted some. After 6 weeks of PT my Quad is not responding! I’m Not able to lift my leg at All! ( when sitting or lying down)by Now my muscle is compt gone! Doc order another 8 wks of PT. Now I go to gym for PT working with weights to strengthen my Quad. But I want to know if it will ever come back and how long will it take? I just read about AMI. At first I thought it was a rupture tendon and Doc order a second MRI but there was nothing “wrong” according to results. It seems like my Doc had never seen anything like this before. I don’t think they believe me at first when I told them that I could’t lift nor hold my leg up when sitting. My first therapist wasn’t giving me the appropriate exercises – I know this now. So for 6 weeks there my muscle prob waisted completely! At begin it was very frustrating for me that they couldn’t tell me what was wrong with my leg. I been doing research on my owed to find out why I couldn’t raise my leg. Please Help!!!

    • Andy Schmidt says:

      I hope this has settled now, but sounds like you either had a severe AMI, or possibly an undiagnosed rupture. Let me know how things have turned out.

  8. Kuljeet says:

    Hi Andy

    Question for you. I had knee surgery two years ago after I heard a pop in my knee. Swelled up a few later as I was playing ball hockey. Original pop was heard playing as well (2012). Surgery was March 2013. They fixed a pLica and articulate cartilage tear on medial side. After surgery about ten weeks in started to hurt again on femoral condyle. A year later had another mri, two more tears in cartilage in apex of knee or around there and pica was back. Had those fixed and micro fracture surgery to femoral condyle and under knee cap. Doc was surprised to see how bad under the knee cap was ( different doc). Now been doing Physio for 8 months post op. Some pain is gone but knee cap is still sore and now hear a clicking noise when I do excercises and my vmo ( quad) on the medial side won’t activate. I haven’t been able to run for two yrs or do lunges or leg extensions at the gym with more than ten pounds. Any suggestions.

    Thx

    KT

    • Andy Schmidt says:

      get used to the clicking, work hard on open chain quads exercises, be careful with loaded exercises , keep the knees tracking over your toes well with cycling, swimming, consider glucosamine. Good luck!

  9. Quratulain says:

    I had knee and ankle injury 7 years ago.i I went to a number of doctors but yet not feel my injured leg like uninjured one.there is muscle atrophy and its weak than normal. I do physiotherapy off and on as the improvement is only temporarliy. Now I feel load on my knee and ankle joint. I fail to understand what to do.

    • Andy Schmidt says:

      Are you completely diligent with your rehab? it takes a long time, and many people dont give it long enough to show results. As PTs, we can’t change the time physiology takes to strengthen a muscle. Work very hard and take the good advice from properly qualified people. Good luck

  10. Caroline says:

    Hi,
    Thanks for the informative article. This past February, I suffered a severe knee injury during a ski incident. I was diagnosed with a tibia avulsion fracture, torn ACL and torn meniscus. When the ACL tore, it ripped off 5 bone fragments with it, which is a rare injury. I had surgery in March and after being in extension for 6 weeks, I was finally able to start PT in late April. My thigh had severly atrophied after surgery of course, but even now…several weeks into PT, the atrophy has not reduced at all. How long does it take for atrophied quad muscle to reduce? Will I ever be able to regain full muscle? will AMI reduce after PT? I still can’t bend my leg past 110° at the moment which is a huge improvement considering I couldn’t bend it at all at start of PT. By the way, I am 18 years old. I just want more information on the healing since my PT and surgeon dismiss me because of my age and don’t answer most of my questions

    thank you!!

    • Andy Schmidt says:

      hi Caroline
      It will take probably between a year and two years for the quads strength to return – and you may always looks a bit atrophied too n the affected side. Keep working at it hard and you will get there, and get that bend going as much as you can. If your providers are dismissive of you, thats not very helpful – look around for someone that does take you seriously, as you need this knee to be good for life! Good luck and hope it goes well

  11. Dipalkumar Shah says:

    I used to do brisk walking of 3 to 3.5 km since last 8 years. I never had any sports injury to knee or thigh. I had right quadriceps tenidinitis 14 months back, treated with physiotherapy. It developed again 9 months back, treated with physiotherapy. 4 months back I developed bilateral quadriceps tendinitis. I took physiotherapy. No I developed significant weakness of quadriceps muscles on both sides. I am not able to walk for few meters pain free. MRI done at 3 months gap shows significant wasting of bilateral quadriceps muscle, more of vastus intermedius. No abnormal signal intensity in tendon or muscle. My EMG and NCV are normal. CPK is normal, serum lactate is elevated. Could it be due to quadriceps muscle inhibition. If yes, how to diagnose it and how to rule out any other condition ? What could be the treatment ? Kindly guide me. Thanks

    • Andy Schmidt says:

      Hi there
      In the absence of injury or pain, arthogenic muscle inhibition of the quadriceps is unlikely. A bilateral weakness generally indicates a central cause – I would encourage further medical/neurological testing of this before engaging in further treatment.

  12. Ellen Marinucci says:

    Three years ago I had revision surgery on my left knee. A serious fall caused the problem. PT was not successful. The surgeon has recommended operating on the muscles surrounding the knee. He said the implant is strong, but the muscles are weak. Does this sound logical? I am limping quite a bit and do need help. Thank you for your assistance.

    • Andy Schmidt says:

      I am not sure what he is going to do by operating on the muscles around the knee? Especially if the implant is strong. Operating on a muscle isn’t normal! I think you need to get a better explanation again from the surgeon about what exactly he is going to do with surgery? I would be happy to comment more once you know this.
      Andy

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